Break and entry crimes are a well documented and, apparently, daily occurrence in many, if not all, cities. Break and entry into commercial retail establishments is a particularly vexing problem in that, on the one hand, it is desirable for the retail establishment to have large attractive displays of their wares behind panoramic glass windows so as to advertise and promote the establishment's wares, and on the other hand, such large windows and their associated displays of wares, provide an enticing target for the criminal element who count on being able to break the glass from the outside and grab the wares on display through the open window frame.
In the prior art, it is common, especially in high crime areas, for commercial retail outlets to have either permanently installed metal bars either in front of or behind the glass storefront displays, thereby, marring the attractiveness of the display, or to have pull down shutters or grates so as to lock an obstacle into place between the glass windows and a person attempting to break and enter. Both of these prior art solutions are not only unsightly, but expensive to install and, in the latter case, unreliable to maintain, in that employees must be relied on to lower and lock into place the shutters or grates.
So called security film has become available more recently to address the problem of break and enter through glass windows. Security film is typically a thin, transparent, polymer film providing a resilient high tensile strength barrier which, when adhered against an interior surface of a glass window, resists complete shattering of the glass when an attempt at penetration is made from the outside. One commercial supplier of security window film are Metallized Products in St. Petersburg, Fla., U.S.A., who supply 12 mil and 14 mil cross weaved polyester film under the trademark Sun-gard. Another supplier of security window film is 3M.TM. who market safety and security film under the trademark Scotchshield. Scotchshield.TM. is held out by 3M.TM. as resisting penetration by keeping the glass in place during attempted break-ins, storms and earthquakes.
However, it is the applicant's experience that merely applying security window film is not sufficient in many instances to prohibit break and enter. In particular, it is quite often the case that a glass window, whether it has security film applied or whether it has embedded wire mesh or the like, will not prevent a break and enter at the hands of a determined assailant because the edges of the glass window are typically not secured to the window frame. Consequently, to affect a break and enter, the glass window, held together by its embedded wire mesh or security window film applied to an inner surface, merely has to be broken and bowed sufficiently to draw the edges of the glass free of the window frame, at which point the entire window may be pushed free of the frame.
In the prior art an attempt to overcome this problem has been made by an entity doing business under the trademark Glasslock in San Jose, Calif., U.S.A. The Glasslock.TM. solution is to extend the edge of security window film beyond the edge of the glass so as to overlap a significant portion of the window frame with security window film. Rigid base plates are then overlaid over the overlapping area. The rigid base plates are screwed into the window frame so as to sandwich the edges of the window security film between the rigid base plate and the window frame. In this fashion, when bowing of the broken glass tensions the film, the tension is resisted by the mechanical mounting of the edges of the window security film to the window frame. In particular, the Glasslock.TM. device is typically employed to bend the edges of the security window film at 90 degrees to the plane of the window so that the mechanical mounting of the film to the window frame by means of screws through the rigid base plate is assisted by bending of the film around an edge of the plate adjacent the window.
Applicant has determined that it is unnecessary and likely counter-productive to perforate the security window film by screws or the like extending through rigid plates. It is, further, unnecessary to bend the film over the edge of the rigid base plate as a means of applying the tensile load from the film to the rigid base plate, although it does help prevent the film merely tearing free of the mounting screws due to the stress concentrations around the holes punctured in the film by the mounting screws.
It is an object of the present invention to provide an adhesive based method and apparatus for adhesively mounting the edge of security window film to a window frame so as to offer tensile resistance to bowing of the glass once broken, so that the same or better result is achieved as compared with the more difficult to install mechanical Glasslock.TM. device which requires a significant window frame depth, and requires drilling and screwing of a rigid base plate to the window frame. It is a further object to provide for adhesively mounting the edge of security window film to the edge of the glass window pane.